Quarter	Millions of US Dollars
1995-07-01	300
1995-10-01	300
1996-01-01	350
1996-04-01	450
1996-07-01	560
1996-10-01	836
1997-01-01	840
1997-04-01	1309
1997-07-01	1407
1997-10-01	2105
1998-01-01	2120
1998-04-01	3124
1998-07-01	3484
1998-10-01	3589
1999-01-01	4099
1999-04-01	4142
1999-07-01	4178
1999-10-01	4705
2000-01-01	4658
2000-04-01	5323
2000-07-01	5537
2000-10-01	6442
2001-01-01	6413
2001-04-01	7429
2001-07-01	8702
2001-10-01	8831
2002-01-01	9823
2002-04-01	10332
2002-07-01	11188
2002-10-01	14471
2003-01-01	15206
2003-04-01	15497
2003-07-01	15105
2003-10-01	15229
2004-01-01	14342
2004-04-01	15551
2004-07-01	16886
2004-10-01	19110
2005-01-01	17892
2005-04-01	20059
2005-07-01	19907
2005-10-01	20889
2006-01-01	21796
2006-04-01	24705
2006-07-01	24500
2006-10-01	24202
2007-01-01	23913
2007-04-01	23930
2007-07-01	24167
2007-10-01	23977
2008-01-01	24062
2008-04-01	24440
2008-07-01	24024
2008-10-01	23996
2009-01-01	26052
2009-04-01	25794
2009-07-01	25468
2009-10-01	23455
2010-01-01	23544
2010-04-01	23384
2010-07-01	23283
2010-10-01	24288
2011-01-01	24861
2011-04-01	25173
2011-07-01	26275
2011-10-01	28849
2012-01-01	28307
2012-04-01	31440
2012-07-01	30671
2012-10-01	34759
2013-01-01	33849
2013-04-01	36374
2013-07-01	36586
2013-10-01	36612
2014-01-01	36612
2014-04-01	37098
2014-07-01	37003
2014-10-01	36963
2015-01-01	38790
2015-04-01	36329
2015-07-01	35830
2015-10-01	37402
2016-01-01	37128
2016-04-01	39103
2016-07-01	39108
2016-10-01	39183
2017-01-01	40777
2017-04-01	40863
2017-07-01	40515
2017-10-01	36392
2018-01-01	35730
2018-04-01	40572